Abstract
Cognitive radio technologies have achieved in the recent years an increasing interest for the possible gain in terms of spectrum usage with respect to unshared approaches. While most of the attention has been devoted to the cognitive coexistence between terrestrial systems, the coexistence between terrestrial and satellite communications is also seen as a viable option. Cognitive radio for satellite communications (CoRaSat) has been a European Commission seventh Framework Program project funded under the ICT Call 8. CoRaSat aimed at investigating, developing, and demonstrating cognitive radio techniques in satellite communication systems for flexible and dynamic spectrum access. In this paper, the CoRaSat cognitive approaches and techniques, investigated, developed, and demonstrated as most relevant to satellite communications, are described. In particular, the focus is on spectrum awareness, that is, database and spectrum sensing approaches, and on spectrum exploitation algorithms, that is, resource allocation and beamforming algorithms, to enable the use of spectrum for satellite communications using shared bands.